Merzļikins spent several years playing hockey in Switzerland for HC Lugano, and was awarded the Jacques Plante Trophy as best goaltender in the National League in both 2016 and 2018.

In the 2016 NLA playoffs, Merzļikins led HC Lugano to the NL final which they would eventually lose in five games to SC Bern.

[6] In the 2017–18 season, Merzļikins captured his second Jacques Plante Trophy as the league's Goaltender of the Year after finishing fourth in wins and fifth in saver percentage with a 19–15–1 record in 40 contests.

He posted a 22–18–0 record with a 2.44 goals against average (GAA), .921 save percentage (SV%) and a career-high five shutouts in 43 games.

[15] At the end of the season, Merzļikins was named to the NHL's All-Rookie Team, the third member of the Blue Jackets to earn the honour.

[17] In the COVID-19 pandemic-shortened season of 2020–21, Merzļikins played well with a 2.77 goals against average and a save percentage of .916, but the Blue Jackets could not score and the team missed the playoffs.

[20] During the following 2021–22 season he struggled; he won more games than he lost, but his individual stats ballooned, with a goals against average of 3.22 save percentage of .907.

He was selected to the national team for the 2016 World Championship, and made his debut in the opening game against Sweden in a 2–1 overtime loss.

Their son is named after former teammate and countryman Matīss Kivlenieks, who died in a fireworks accident on 4 July 2021, protecting Merzļikins and his family.